Doping parameters

The parent (A2B0CU-O4) cuprates are antiferromagnetic semiconductors which, on doping to A2-xBxCu-04, become superconductors where x is called the doping parameter. The replacement of Nd3 by Ce4+ produces an electron superconductor... 

Cuprate superconductors exhibit complicated phase diagrams which are functions of the doping parameter, x which controls the amount of the electron-transfer into or out of the cuprate plane. See for example Fig. 8.2. 

Fig. 8.8. The dependence of resonance exchange integral on doping parameter...

Figure 6 shows the field dependence of hole mobiUty for TAPC-doped bisphenol A polycarbonate at various temperatures (37). The mobilities decrease with increasing field at low fields. At high fields, a log oc relationship is observed. The experimental results can be reproduced by Monte Carlo simulation, shown by soHd lines in Figure 6. The model predicts that the high field mobiUty follows the following equation (37) where d = a/kT (p is the width of the Gaussian distribution density of states), Z is a parameter that characterizes the degree of positional disorder, E is the electric field, is a prefactor mobihty, and Cis an empirical constant given as 2.9 X lO " (cm/V). ...

Table 3 summarizes some of the present state-of-the-art parameters obtained for undoped and doped i -SiH(F) material thus produced. The device-quahty material exhibits semiconductivity because In G vs 10 /Texhibits a straight line with a conductivity activation energy of eV, which is... 

Doping of alkali-metals into CNTs has been examined [11]. The X-ray powder diffraction (XRD) patterns of the K- or Rb-doped CNTs show that alkali-metals are intercalated between the CNT layers. The hexagonal unit cell is essentially the same as that of the stage-1 alkali-metal intercalated graphite ACg (A=K, Rb). For a sample doped with Rb, the observed lattice parameter of the perpendicular... 

Cook (Ref 21) presents a thermo-hydrodynamic calcn of the detonation parameters and detonation products of two NS expls containing 25/1.5/73.5 NS/A1/AN-SN dope and 27-5/3/ 69.5 NS/A1/AN-SN dope... 

Velapoldl et al. (64) used a similar approach but prepared fibers of uniform diameter (5-45 pm) from Inorganic Ion-doped glasses. The fluorescence parameters of these materials can be changed by substituting various Ions, such as Tb , Sm , Eu , Mn, UOj, Cu, and Sn. They show excellent stability under Irradiation using Incident excitation (measurement Imprecision of 1% under continuous Irradiation In the microscope for 24 h) and have a fluorescence flux density proportional to the fiber length. 

The approach to standardization used by Haaijman (53) and others (66,67), in which the fluorophor is incorporated within or bound to the surface of a plastic sphere, is more versatile than the use of inorganic ion>doped spheres, since the standard can be tailored exactly to the specifications required by the analyte species. However, this approach increases the uncertainty of the measurement because the photobleaching characteristics of both the standard and the sample must be considered. The ideal approach is to employ both types of standards. The glass microspheres can be used to calibrate instruments and set instrument operating parameters on a day-to-day basis, and the fluorophor-doped polymer materials can be used to determine the concentration-instrument response function. 

This contribution Is concerned with the magnetic and Mossbauer characterization of (a) Fe/zeollte (mordenlte) systems, and that of (b) Fe and/or Ru on boron-doped carbon substrates. Some correlations between the characterization and CO hydrogenation parameters will be pointed out. Because of limitations of space, we shall present salient features of these Investigations. At the outset. It would be befitting to present a succinct background on the basic principles of magnetic and Mossbauer characterization. 

For symmetric PS-fo-P4VP (20 000 19 000) diblock copolymer films with the wormlike phase separation structures, the TCPP-doped films were irradiated using one laser shot with a fluence of 150 mJ cm in air. The ablation phenomenon is observed for this irradiation fluence (Figure 12.5c and f), but it is difficult to conclude that this is a selective ablation of the doped-P4VP parts. We cannot deny the possibility that the decomposition of the P4VP parts affects the PS parts because of the existence of large interfaces between the two symmetric blocks in wormlike structures. Thus, for the site-selective ablation of diblock copolymer films, the surface morphology of the phase separation structures is one of the most important parameters. 

In eadi specific case the choice of an adsorbent, electrophysical parameters and the method of registration of its change as well as the choice of various pre-adsorption treatment techniques of the surface of adsorbent is dictated by the type and nature of analytical problem to be solved. For instance, if particles active from the standpoint of the change in electrophysical parameters of semiconductor adsorbent occur on the surface of the latter due to development of a chemical reaction involving active particles, it is natural to use either semiconductor material catalyzing the reaction in question or if this is not possible specific surface dopes accelerating the reaction. Above substances are used as operational element of the sensor. If such particles occur as a result of adsorption from adjacent volume, one can use semiconductor materials with maximum adsorption sensitivity to the chosen electrophysical parameter with respect to a specific gas as operational element. 

In general, the peculiarities of the surface effects in thin semiconductors, for which application of semi-infinite geometry becomes incorrect were examined in numerous papers. As it has been shown in studies [101, 113, 121 - 123] the thickness of semiconductor adsorbent becomes one of important parameters in this case. Thus, in paper [121] the relationship was deduced for the change in conductivity and work function of a thin semiconductor with weakly ionized dopes when the surface charge was available. Paper [122] examined the effect of the charge on the temperature dependence of the work function and conductivity of substantially thin adsorbents. Papers [101, 123] focused on the dependence of the surface conductivity and value of the surface charge as functions of the thickness of semiconductor and value of the surface band bending caused by adsorption and application of external field. 

The first the methods mentioned is based on the monitoring of initial changes in electric parameters (mainly the dope conductivity o) of semiconductor film of sensor caused by adsorption of active particles. In the limiting case this value may be estimated as... 

The determination of the electronic structure of lanthanide-doped materials and the prediction of the optical properties are not trivial tasks. The standard ligand field models lack predictive power and undergoes parametric uncertainty at low symmetry, while customary computation methods, such as DFT, cannot be used in a routine manner for ligand field on lanthanide accounts. The ligand field density functional theory (LFDFT) algorithm23-30 consists of a customized conduct of nonempirical DFT calculations, extracting reliable parameters that can be used in further numeric experiments, relevant for the prediction in luminescent materials science.31 These series of parameters, which have to be determined in order to analyze the problem of two-open-shell 4f and 5d electrons in lanthanide materials, are as follows. 

Wenger OS, Giidel HU (2003) Influence of Crystal Field Parameters on Near-Infrared to Visible Photon Upconversion in Ti2+ andNi2+ Doped Halide Lattices 106 59-70 Wheatley AEH, see Linton DJ (2003) 105 67-139 Wilhelm M, see Haubner R (2002) 102 1-46... 

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